From 8affdbb3e2ef6b6a3a467b87dc336dc601dc2ed9 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 15 Feb 2024 19:25:30 +0100 Subject: [PATCH] mptcp: fix lockless access in subflow ULP diag commit b8adb69a7d29c2d33eb327bca66476fb6066516b upstream. Since the introduction of the subflow ULP diag interface, the dump callback accessed all the subflow data with lockless. We need either to annotate all the read and write operation accordingly, or acquire the subflow socket lock. Let's do latter, even if slower, to avoid a diffstat havoc. Fixes: 5147dfb50832 ("mptcp: allow dumping subflow context to userspace") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/tcp.h | 2 +- net/mptcp/diag.c | 6 +++++- net/tls/tls_main.c | 2 +- 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 5c03dc6d0f79..d6e4b6f7d6ce 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2224,7 +2224,7 @@ struct tcp_ulp_ops { /* cleanup ulp */ void (*release)(struct sock *sk); /* diagnostic */ - int (*get_info)(const struct sock *sk, struct sk_buff *skb); + int (*get_info)(struct sock *sk, struct sk_buff *skb); size_t (*get_info_size)(const struct sock *sk); /* clone ulp */ void (*clone)(const struct request_sock *req, struct sock *newsk, diff --git a/net/mptcp/diag.c b/net/mptcp/diag.c index a536586742f2..e57c5f47f035 100644 --- a/net/mptcp/diag.c +++ b/net/mptcp/diag.c @@ -13,17 +13,19 @@ #include #include "protocol.h" -static int subflow_get_info(const struct sock *sk, struct sk_buff *skb) +static int subflow_get_info(struct sock *sk, struct sk_buff *skb) { struct mptcp_subflow_context *sf; struct nlattr *start; u32 flags = 0; + bool slow; int err; start = nla_nest_start_noflag(skb, INET_ULP_INFO_MPTCP); if (!start) return -EMSGSIZE; + slow = lock_sock_fast(sk); rcu_read_lock(); sf = rcu_dereference(inet_csk(sk)->icsk_ulp_data); if (!sf) { @@ -69,11 +71,13 @@ static int subflow_get_info(const struct sock *sk, struct sk_buff *skb) } rcu_read_unlock(); + unlock_sock_fast(sk, slow); nla_nest_end(skb, start); return 0; nla_failure: rcu_read_unlock(); + unlock_sock_fast(sk, slow); nla_nest_cancel(skb, start); return err; } diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c index 7ee3c8b03a39..2bbacd9b97e5 100644 --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -800,7 +800,7 @@ static void tls_update(struct sock *sk, struct proto *p, } } -static int tls_get_info(const struct sock *sk, struct sk_buff *skb) +static int tls_get_info(struct sock *sk, struct sk_buff *skb) { u16 version, cipher_type; struct tls_context *ctx;